Building Better Joints

Artificial hips and knees help hundreds of thousands of people return to active lifestyles every year. With an aging population, joint replacements in America are expected to rise—a lot. The American Academy of Orthopaedic Surgeons anticipates a 174 percent increase in hip replacements and a 673 percent increase in knee replacements over the next 20 years.

By studying how the material used to make these artificial joints breaks down over time, researchers at Case Western Reserve hope to provide manufacturers with new information on how to make longer-lasting implants.

Strong and slick, ultra-high molecular weight polyethylene makes a great substitute for joints—but it’s not perfect. Inside the body, chemical oxidation degrades the material over time, leaving 40,000 Americans needing a second—or even a third— replacement knee or hip every year.

Through a five-year National Science Foundation-CAREER grant, metallic nanostructures expert and assistant professor of chemistry Anna Samia, PhD, and her team will mimic how the implants age in the body. They will simulate the chemical stress by imbedding magnetic nanoparticles in the material, and then use the magnetic signal to create images to show what’s happening inside the plastic.

Samia says these methods and technologies also could be used to study how stents, electrodes, artificial organs and other implants degrade inside the body.